Shedding light on dark DNA Most textbook definitions of evolution state that it occurs in two stages: mutation followed by natural selection. DNA mutation is a common and continuous process, and occurs completely at random.
The average adult only eats 15 grams of fiber per day. Women need 25 grams of fiber per day, and men need 38 grams per day, according to the Institute of Medicine.
How Many Grams of Fiber Per Day for Seniors. For men and women older than 50 the fiber requirements go down to 30 for men and 21 for women. This is due to the assumption that older people have a lower calorie intake and are less active during the day.